1. Field of the Invention
The present invention is in the field of manufacturing a gate contact on a semiconductor material using light actuated optical photomasking techniques for generating a structured doping, metal deposition, or the like.
2. Description of the Prior Art
It has been known for more than a decade to produce self-aligned metal contacts, particularly gate contacts on silicon as a semiconductor material, the adjustment being used in conjunction with a source and/or drain region, a source and/or drain contact, a gate region, or a channel region or the like. The application of light-sensitive optical photolithography with masks for doping and/or deposition of metal for contacts and the like also is well known, utilizing light essentially in the visible wavelength range. As is known, there is a lower limit for the dimensions to be produced by exact and sharp-edged imaging of mask structures, this lower limit being dependent on the order of magnitude of the light wavelength employed so that a dimension that is significantly smaller than the wavelength of light employed in photolithography can no longer be reliably observed.
With application of light-optical photolithography alone, sharp contours could only be produced down to dimensions which are of the order of several tenths of a micron, as a minimum.
In Solid State Technology (February 1985), pages 209 to 215, there are disclosed details for the manufacture of gallium arsenide MESFET's for semiconductor materials from Groups III and V of the Periodic Table. The gate contact therein has a dimension of about 1 micron as viewed in the direction between the source and the drain. Spacings measuring at least that size exist between the gate contact and the source or the drain contact.
Further prior art is discussed in IEDM (1964) pages 194 to 197; GaAs IC Symp. Tech. Digest (1983), pages 138 through 141; Extended Abstracts of the 15th Conference on Solid State Devices and Materials, Tokyo 1983, pages 69 to 72; 12th International Symposium on GaAs and related compounds, Karuizawa, 1985, IEE ED-32 (1985), pages 848 to 850; Electronics Letters, Vol. 21 (1985), pages 804 to 805, and GaAs IC Symposium, IEE (1984), page 121. European OS No. 01 30 416 is related to the extent that it deals with the manufacture of a high-temperature resistant contact.